In a conventional patterning process for semiconductor device fabrication, a photoresist pattern may be formed on a film (for example, a silicon film, a dielectric film, or a conductive film) to be etched for pattern formation. The film may be etched using the photoresist pattern as an etching mask to form a desired pattern.
With increases in integration densities of semiconductor devices, smaller critical dimensions (CDs) and/or new lithography techniques may be needed to form fine patterns including contact holes having smaller opening sizes or spaces having smaller widths. For realization of such fine patterns, high-resolution photolithography and photoresist materials with resistance to dry etching may be needed. However, it may be difficult to simultaneously satisfy resolution and dry etching characteristics. To provide relatively high resolution and wide DOF (depth of focus), the thickness of a resist film may be reduced. A reduced resist film thickness, however, may deteriorate dry etching characteristics.
In this respect, various technologies have been suggested to reduce the above-described problem. For example, a chemical surface treatment of a photoresist pattern with a dry-etching resistant material has been proposed. In particular, silicon-containing compounds with resistance to dry etching have been studied.
For example, U.S. Pat. No. 6,110,637 discloses a technology of forming a fine pattern by crosslinking reaction between a photoresist with a carboxylic acid anhydride functional group and an aminosiloxane oligomer. This technology, however, may require a specific photoresist material capable of crosslinking with aminosiloxane and a separate organic solvent for removal of a non-crosslinked silicon-containing material.
U.S. Patent Publication No. 2004/0009436 A1 discloses a technology of coating a silicon-containing material layer on a resist pattern using a crosslinking reaction between a silicon-containing water-soluble polymer and the resist pattern. According to this technology, silicon content may be restricted, and thus, a sufficient resistance to dry etching may be difficult to obtain.